In recent years, the acreage of lily has increased in Taiwan. For example, the acreages in 1995 and 1998 were 155 and 345 hectares, and the market value for these two years was NT$ 380. and 800 millions, respectively. Lily has become a potentially economic plant in Taiwan.
Lily gray mold caused by Botrytis elliptica (Berk) Cook was the most severe and destructive disease in the field and resulted in catastrophic economic losses. This phytopathogenic fungus leads to necrotic lesions and rots on leaves and flowers when there exist conducive environmental factors. Genus of Botrytis consists of 22 species. In Taiwan, Botrytis mainly comprises B. cinerea Pers, B. elliptica (Berk.) Cooke, B. gladiolorum Timmermans, B. liliorum Fujik and B. allii-fistulosis Sawada. Optimal temperatures and relative humidity for the growth of these species are 18 to 25° C. and 95 to 100%, respectively.
The gray mold disease of lily generally occurred from December to next March. For controlling this disease, fungicides were frequently used. However, several drawbacks were worthy of our attention. One of them is Botrytis spp. may develop resistance to specific fungicides like benzimidazoles, dicarboximides, diethofencarb or two sterol biosynthesis inhibitors within a relatively short period of time, thus increasing the difficulty of the gray mold control. Moreover, various kinds of pollution generated from the usage of the fungicides may become serious environmental problems. Therefore, an alternative solution such as biological control is a practical method because it is endurable, economical, stable and environmental compatible.
Based on the above descriptions, a competent antagonist isolated from lily is a good candidate for lily gray mold control. It is worthy to note that, however, the antagonist should have following abilities: allowing lily to adapt to the niche short of nutrients, tolerances to direct exposure of UV radiation and rush fluctuations of the temperature and relative humidity. In addition, the antagonist has to vie with other epiphytes successfully. A sound formulation that ensures the stability of the long-term storage of antagonists, enhances the ability of disease control and warrants the commercial value of biocontrol agents is also important.
Due to the gray mold disease not only attacking the lily but other valuable economic plants, it is important to inhibit the pathogenic fungus via biological control.